U.S. patent number 11,261,675 [Application Number 16/249,329] was granted by the patent office on 2022-03-01 for methods for constructing a helical strake segment using one or more shell sections and fins.
This patent grant is currently assigned to VIV SOLUTIONS LLC. The grantee listed for this patent is VIV Solutions LLC. Invention is credited to Donald Wayne Allen.
United States Patent |
11,261,675 |
Allen |
March 1, 2022 |
Methods for constructing a helical strake segment using one or more
shell sections and fins
Abstract
A helical strake for suppressing a vortex induced vibration
(VIV) of a tubular. The helical strake having a shell dimensioned
to at least partially encircle an underlying tubular, the shell
having at least one fin opening; and at least one fin dimensioned
to be positioned within the at least one fin opening formed by the
shell, the at least one fin having a base portion dimensioned to be
positioned along an underlying tubular and a tail portion
dimensioned to extend through the at least one fin opening and
radially outward from an underlying tubular.
Inventors: |
Allen; Donald Wayne (Richmond,
TX) |
Applicant: |
Name |
City |
State |
Country |
Type |
VIV Solutions LLC |
Richmond |
TX |
US |
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Assignee: |
VIV SOLUTIONS LLC (Richmond,
TX)
|
Family
ID: |
67213667 |
Appl.
No.: |
16/249,329 |
Filed: |
January 16, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190218866 A1 |
Jul 18, 2019 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62618046 |
Jan 16, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B
17/22 (20130101); E21B 17/01 (20130101) |
Current International
Class: |
F16L
57/00 (20060101); F16L 1/12 (20060101); F15D
1/10 (20060101); E02B 17/00 (20060101); E21B
17/01 (20060101); E21B 17/22 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2525123 |
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Nov 2012 |
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EP |
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2335248 |
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Sep 1999 |
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GB |
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2362444 |
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Nov 2001 |
|
GB |
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WO 01/77563 |
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Oct 2001 |
|
WO |
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WO2005026560 |
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Mar 2005 |
|
WO |
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WO2007/106736 |
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Sep 2007 |
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WO |
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WO2008064102 |
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May 2008 |
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WO |
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WO2009070483 |
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Jun 2009 |
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WO |
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WO 2011/022332 |
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Feb 2011 |
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WO |
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WO-2018231061 |
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Dec 2018 |
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WO |
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Other References
Allen, D.W. et al., "Henning Devices: A New Class of VIV
Suppression Apparatus for Offshore Tubulars", Offshore Technology
Conference 19881, May 4-7, 2009, pp. 1-9. cited by applicant .
Lee, L. et al., "Blade Henning Devices for VIV Supression of
Offshore Tubulars", Proceedings of OMAE:28.sup.th International
Conference on Ocean, Offshore and Arctic Engineering, Shell Global
Solutions (US) Inc., May 31-Jun. 5, 2009, pp. 1-6. cited by
applicant.
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Primary Examiner: Troutman; Matthew
Assistant Examiner: Wood; Douglas S
Attorney, Agent or Firm: Womble Bond Dickinson (US) LLP
Claims
What is claimed is:
1. A helical strake for suppressing a vortex induced vibration
(VIV) of a tubular, the helical strake comprising: a shell
dimensioned to at least partially encircle an underlying tubular,
the shell having at least one shell wall that defines a fin
opening; and at least one fin dimensioned to be positioned through
the at least one fin opening formed by the shell, the at least one
fin having a base portion dimensioned to be positioned along an
underlying tubular and a tail portion dimensioned to extend through
the at least one fin opening and radially outward from an
underlying tubular and the shell, and wherein the fin comprises a
length dimension and a width dimension that is less than the
length, and the width dimension tapers continuously from the base
portion to an end of the tail portion.
2. The helical strake of claim 1 wherein the fin opening comprises
an elongated opening having a longitudinal opening axis that is at
an angle to a longitudinal shell axis of the shell.
3. The helical strake of claim 1 wherein the at least one fin
comprises a plurality of fin segments that extend from a first end
to a second end of the shell.
4. The helical strake of claim 1 wherein the at least one fin
comprises a continuous fin that extends from a first end to a
second end of the shell.
5. The helical strake of claim 1 wherein the shell comprises a
plurality of fin openings that extend from an inner surface of the
shell facing the tubular to an outer surface of the shell facing
away from the tubular, and the plurality of fin openings are
helically arranged around the shell.
6. The helical strake of claim 5 wherein the at least one fin
comprises a plurality of fins that are helically arranged around
the underlying tubular when positioned within the plurality of fin
openings.
7. The helical strake of claim 1 wherein the shell comprises a
first shell member, a second shell member and a third shell member
that form at least three fin openings circumferentially spaced
around an underlying tubular.
8. The helical strake of claim 7 wherein the first shell member,
the second shell member and the third shell member are separate
structures that each comprise a center portion positioned along the
underlying tubular and a pair of flanges extending radially outward
from the center portion, and wherein the fin openings are formed
between the flanges of adjacent ones of the first, second and third
shell members.
9. The helical strake of claim 1 further comprising a slot formed
through the at least one fin, the slot dimensioned to receive a
band for securing the at least one fin and the shell to the
underlying tubular.
10. A helical strake for suppressing a vortex induced vibration
(VIV) of a tubular, the helical strake comprising: a shell
dimensioned to at least partially encircle an underlying tubular,
the shell having a plurality of circumferentially spaced fin
openings formed through the shell; and a plurality of fins
dimensioned to be positioned through the plurality of
circumferentially spaced fin openings such that a tail portion of
each of the plurality of fins is exposed through the fin openings
and a base portion rests against an underlying tubular, wherein
each of the plurality of fins have a width dimension that is less
than a length dimension, and the width dimension of each of the
plurality of fins tapers continuously from the base portion to an
end of the tail portion, and wherein the plurality of fins are in a
helical arrangement when positioned through the fin openings.
11. The helical strake of claim 10 wherein the shell comprises a
plurality of shell members that are connected together to
completely encircle the underlying tubular.
12. The helical strake of claim 10 wherein at least one opening of
the plurality of circumferentially spaced fin openings is an
elongated opening extending between a first end and a second end of
the shell, and at least one fin of the plurality of fins is a
continuous fin.
13. The helical strake of claim 10 wherein at least two openings of
the plurality of circumferentially spaced openings are helically
arranged between a first end and a second end of the shell, and at
least one fin of the plurality of fins comprises at least two
discrete fin segments positioned in the at least two openings.
14. The helical strake of claim 10 wherein a shape of a
cross-section of the plurality of fins along the width dimension is
a triangular shape and the widest part of the triangular shape is
wider than the plurality of openings.
Description
CROSS-REFERENCE TO RELATED APPLICATION
The application is a non-provisional application of U.S.
Provisional Patent Application No. 62/618,046, filed Jan. 16, 2018,
which is incorporated herein by reference.
FIELD
A helical strake segment including shell segments with, or without,
discrete fins. Other embodiments are also described herein.
BACKGROUND
A difficult obstacle associated with the exploration and production
of oil and gas is management of significant ocean currents. These
currents can produce vortex-induced vibration (VIV) and/or large
deflections of tubulars associated with drilling and production.
VIV can cause substantial fatigue damage to the tubular or cause
suspension of drilling due to increased deflections. A common
device for suppressing VIV is a helical strake.
A helical strake may include a shell with fins attached to the
shell in a helical arrangement to disrupt the flow. Helical strakes
control the point at which the oncoming current separates from the
helical strake thereby controlling, and shortening, correlation
length of the vortex shedding. This decreased correlation length
reduces VIV due to both weaker vortices and near random phasing of
the various vortices that are shed along the tubular span.
SUMMARY
The present invention is directed to methods for fabricating a
helical strake using discrete fins and/or with minimal mold costs.
A recent development for constructing a helical strake is to
eliminate the shell and simply band rigid fins to the tubular, also
referred to as banded fins. These fins, however, are difficult to
construct. In addition, helical strakes having a shell are often
still required on a portion of the tubular in order to coat the
fins and shell with a coating to inhibit marine growth. While it is
possible to produce an entire mold when a large number of helical
strakes having a shell are required, it can be cost prohibitive
when the quantity required is moderate or low. Thus, the instant
invention proposes a method for fabricating a helical strake with a
shell when the quantity of fins is moderate or low, and optionally
when banded fins for the same size tubular are already being
constructed. The invention further contemplates a cost effective
method for fabricating helical strakes having a shell utilizing
discrete fins.
Representatively, in one aspect, the invention is directed to a
helical strake for suppressing a vortex induced vibration (VIV) of
a tubular. The helical strake may include a shell dimensioned to at
least partially encircle an underlying tubular and having at least
one fin opening, and at least one fin dimensioned to be positioned
within the at least one fin opening formed by the shell. The at
least one fin may have a base portion dimensioned to be positioned
along an underlying tubular and a tail portion dimensioned to
extend through the at least one fin opening and radially outward
from an underlying tubular. In some aspects, the at least one fin
opening is an elongated opening having a longitudinal opening axis
that is at an angle to a longitudinal shell axis of the shell. The
at least one fin may include a plurality of fin segments that
extend from a first end to a second end of the shell, or may be a
continuous fin that extends from a first end to a second end of the
shell. The shell may include a plurality of fin openings, and the
plurality of fin openings are helically arranged around the shell.
In some aspects, the at least one fin may include a plurality of
fins that are helically arranged around the underlying tubular when
positioned within the plurality of fin openings. The shell may
include a first shell member, a second shell member and a third
shell member that form at least three fin openings
circumferentially spaced around an underlying tubular. The first
shell member, the second shell member and the third shell member
may be separate structures that each include a center portion
positioned along the underlying tubular and a pair of flanges
extending radially outward from the center portion, and wherein the
fin openings are formed between the flanges of adjacent ones of the
first, second and third shell members. In some embodiments, the at
least one fin is a T shaped fin and the base portion is wider than
the at least one fin opening. In addition, the strake may include a
slot formed through the at least one fin, the slot dimensioned to
receive a band for securing the at least one fin and the shell to
the underlying tubular.
In another aspect, the invention is directed to a helical strake
for suppressing a vortex induced vibration (VIV) of a tubular
including a shell dimensioned to at least partially encircle an
underlying tubular, the shell having a plurality of
circumferentially spaced fin openings formed through the shell, and
a plurality of fins dimensioned to be positioned within the
plurality of circumferentially spaced fin openings, and wherein the
plurality of fins are in a helical arrangement when positioned
within the fin openings. The shell may include a plurality of shell
members that are connected together to completely encircle the
underlying tubular. In some cases, at least one opening of the
plurality of circumferentially spaced fin openings is an elongated
opening extending between a first end and a second end of the
shell, and at least one fin of the plurality of fins is a
continuous fin. In still further aspects, at least two openings of
the plurality of circumferentially spaced openings are helically
arranged between a first end and a second end of the shell, and at
least one fin of the plurality of fins comprises at least two
discrete fin segments positioned in the at least two openings. The
plurality of fins may have a triangular shape comprising a base
portion that is wider than the plurality of openings and rests
against an underlying tubular while a tail portion extends through
the plurality of openings.
In still further aspects, the invention is directed to a helical
strake for suppressing a vortex induced vibration (VIV) of a
tubular including a shell comprising a plurality of shell members
that are dimensioned to at least partially encircle an underlying
tubular, the shell members having a center portion that conforms to
a shape of the underlying tubular and a pair flanges that extend
radially outward from opposite sides of the center portion, and
wherein the pair of flanges of one of the shell members are
dimensioned to align with the pair of flanges of adjacent shell
members to form a plurality of helical extension member along the
underlying tubular. In some embodiments, the plurality of
circumferentially spaced fin openings are formed between the
flanges of the plurality of shell members, and the strake further
comprises a plurality of fins dimensioned to be positioned within
the plurality of circumferentially spaced fin openings. The flanges
may conform to a shape of the plurality of fins positioned within
the plurality of circumferentially spaced fin openings and hold the
fins against an underlying tubular. Each of the plurality of fins
may include a base portion that is positioned between the shell and
the underlying tubular and a tail portion that extends through the
plurality of fin opening. A fastener may be used to secure the
flanges to each other or the plurality of fins.
The above summary does not include an exhaustive list of all
aspects of the present invention. It is contemplated that the
invention includes all apparatuses that can be practiced from all
suitable combinations of the various aspects summarized above, as
well as those disclosed in the Detailed Description below and
particularly pointed out in the claims filed with the application.
Such combinations have particular advantages not specifically
recited in the above summary.
BRIEF DESCRIPTION OF THE DRAWINGS
The embodiments disclosed herein are illustrated by way of example
and not by way of limitation in the figures of the accompanying
drawings in which like references indicate similar elements. It
should be noted that references to "an" or "one" embodiment in this
disclosure are not necessarily to the same embodiment, and they
mean at least one.
FIG. 1A is a side view of a helical strake segment consisting of a
shell and discrete fins.
FIG. 1B is cross section A-A' of Fig. la and shows a helical strake
segment consisting of a shell and discrete fins.
FIG. 1C is a perspective view of a helical strake segment having
discrete fins and adjoining shell members.
FIG. 1D is cross section B-B' of FIG. 1C and shows a helical strake
segment with discrete fins and adjoining shell members.
FIG. 1E is a cross section of a helical strake showing T-shaped
fins and adjoining shell members.
FIG. 1F is a cross section of a helical strake showing T-shaped
fins and adjoining shell members with the fins fastened to the
shell members.
FIG. 1G is a perspective view of a helical strake segment made up
of adjoining shell members and having a single split for fitting
around a tubular.
FIG. 1H is cross section C-C' of FIG. 1G showing a helical strake
section made up of adjoining shell members and having a single
split for fitting around a tubular.
FIG. 1I is cross section of another embodiment of a helical
strake.
FIG. 1J is cross section of another embodiment of a helical
strake.
DETAILED DESCRIPTION
In this section, we shall explain several preferred embodiments
with reference to the appended drawings. Whenever the shapes,
relative positions and other aspects of the parts described in the
embodiments are not clearly defined, the scope of the embodiments
is not limited only to the parts shown, which are meant merely for
the purpose of illustration. Also, while numerous details are set
forth, it is understood that some embodiments may be practiced
without these details. In other instances, well-known structures
and techniques have not been shown in detail so as not to obscure
the understanding of this description.
The terminology used herein is for the purpose of describing
particular aspects only and is not intended to be limiting of the
invention. Spatially relative terms, such as "beneath", "below",
"lower", "above", "upper", and the like may be used herein for ease
of description to describe one element's or feature's relationship
to another element(s) or feature(s) as illustrated in the figures.
It will be understood that the spatially relative terms are
intended to encompass different orientations of the device in use
or operation in addition to the orientation depicted in the
figures. For example, if the device in the figures is turned over,
elements described as "below" or "beneath" other elements or
features would then be oriented "above" the other elements or
features. Thus, the exemplary term "below" can encompass both an
orientation of above and below. The device may be otherwise
oriented (e.g., rotated 90 degrees or at other orientations) and
the spatially relative descriptors used herein interpreted
accordingly.
As used herein, the singular forms "a", "an", and "the" are
intended to include the plural forms as well, unless the context
indicates otherwise. It will be further understood that the terms
"comprises" and/or "comprising" specify the presence of stated
features, steps, operations, elements, and/or components, but do
not preclude the presence or addition of one or more other
features, steps, operations, elements, components, and/or groups
thereof.
The terms "or" and "and/or" as used herein are to be interpreted as
inclusive or meaning any one or any combination. Therefore, "A, B
or C" or "A, B and/or C" mean "any of the following: A; B; C; A and
B; A and C; B and C; A, B and C." An exception to this definition
will occur only when a combination of elements, functions, steps or
acts are in some way inherently mutually exclusive.
Referring now to the invention in more detail, FIG. 1A shows side
perspective view of a helical strake segment 101 around tubular
100. Helical strake segment 101 is made up of shell 102 and fins
103 extending through openings 104 in shell 102. Openings 104 are
dimensioned to receive fins 103. Fins 103 may extend in a helical
arrangement between a first end 180 and a second end 182 of shell
102. Fins 103 may be discrete fins that are inserted through
openings 104. In other words, fins 103 are separate structures from
one another, and shell 102, prior to assembly of strake section
101. Shell 102 is a cylindrical (or nearly cylindrical) structure
that has openings 104 cut out of the structure to allow for
insertion of fins 103. Any number of openings 104 and fins 103 may
be present. The openings 104 and fins 103 may be in a helical
arrangement along shell 102. For example, openings 104 and/or fins
103 may be elongated members having a longitudinal axis 184, which
is at an angle to, or otherwise not parallel to, the longitudinal
axis 186 of shell 102, such that when fins 103 are positioned
within openings 104, they are helically arranged along shell 102.
Fins 103 may be discrete segments such that gaps are formed between
adjacent fins or may be made more continuous including fins 103
that extend through the entire length, or nearly the entire length,
of helical strake segment 101 and shell 102 without gaps between
adjacent fins.
Still referring to FIG. 1A, any number of fins 103 may be present
and any number of fins may be present around the circumference at
any axial location of shell 102 or helical strake segment 101. Fins
103 may be separated by any suitable gap along a single helix and
may be separated by any angle or length along the circumference of
shell 102 or helical strake segment 101. Fins 103 may be of any
suitable geometry including, but not limited to, T-shaped, round,
oval, trapezoidal, rectangular, triangular, or any variation or
combination thereof. Fins 103 may be any combination of straight
and rounded sides. Fins 103 on a given helical strake segment 101
or shell 102 may all be the same of may be different, even along a
single helix. Once inserted through openings 104, fins 103 may be
attached to shell 102 by any suitable means including, but not
limited to, chemical bonding, fastening with nuts, bolts, rivets,
clamps, or other mechanical means, and welding. In some
embodiments, however, the base of fins 103 under shell 102, are
larger than the associated openings 104. Fins 103 can therefore be
sufficiently restrained against shell 102, once helical strake
segment 101 is attached to, or banded to, tubular 100, without any
additional attachment means between fins 103 and shell 102.
Helical strake segment 101 may be attached to tubular 100 by any
suitable means including, but not limited to, banding, clamping,
fastening, chemical bonding, or by the use of other intermediate
structures. Shell 102 and fins 103 may have coatings or other
structures on their interior or their exterior, or both their
interior and their exterior, such as anti-fouling coatings or
copper (or copper alloy) bar. Helical strake segment 101 may be of
any suitable length, diameter, or cross section. Shell 102 may have
any suitable length, diameter, or cross section and may have a
cross section that varies along its length. Fins 103 may have
openings for bands, springs, or other structures. Shell 102 may
have openings for bands, springs, or other structures. Shell 102
and fins 103 may have openings for other reasons such as for heat
transfer from or to the underlying structure or to improve the
performance of an underlying cathodic protection coating, system,
or structure. Shell 102 may have indentations so that part of shell
102 is spaced off of tubular 100. Openings 104 may be of any
suitable size or shape.
Still referring to FIG. 1A, shell 102 and fins 103 may be made of
any suitable material including, but not limited to, plastic,
metal, fiberglass, composite, synthetic, rubber or elastomer, and
wood. Shell 102 and fins 103 may be made of the same material or
may be made of different materials. Materials may be mixed or
matched as suitable for helical strake segment 101 and its
components.
Referring now to FIG. 1B, FIG. 1B a cross sectional end view of
helical strake segment 101 of FIG. 1A. Helical strake segment 101
may include shell 102, which is made up of shell members 102A,
102B, and 102C, and fins 103 extending through openings 104. From
this view, it can be seen that fins 103 extend through openings 104
in shell 102 that may, or may not, be wider than the base of fins
103. For example, in some embodiments, fins 103 may have a base
portion 170 and a tail portion 172 that extends from the base
portion. The base portion 170 may have a width dimension (W1) that
is larger than a width dimension (W2) of opening 104. In this
aspect, the base portion 170 does not fit through opening 104 and
is held against the tubular by the shell 102, while the tail
portion 172 extends through opening 104, and radially outward from
the base portion and tubular (and the shell portion surrounding the
tubular). Shell members 102A, 102B and 102C may be attached to one
another, or separate from one another. For example, if fins 103 are
formed by separate fin segments extending from one end to another
of strake segment 101 as shown in FIG. 1A, shell members 102A-102C
may be attached to another between the fin segments. Alternatively,
if fins 103 are continuous, that is if fins 103 are continuous from
one end to another of helical strake segment 101 in FIG. 1A, then
shell members 102A, 102B, and 102C can be discrete members that are
optionally attached to fins 103 by any suitable means.
Referring now to FIG. 1C, FIG. 1C shows a side perspective view of
another embodiment of a helical strake. Representatively, helical
strake segment 111 is shown including shell members 112 and fins
113 with slots 115 extending through shell members 112 and fins
113. Shell members 112 may extend both between adjacent fins 113
and also along at least part of the surface of fins 113. If shell
members 112 extend along the sides of fins 113 that project away
from the surface of the underlying tubular (not shown), then slots
115 will extend through both shell members 112 and fins 113.
However, it is not necessary for shell members 112 to extend along
the sides of fins 113 that project away from the surface of the
underlying tubular, for example fins 113 can have base members that
are extend circumferentially and thus shell members 112 can be
attached to those base members leaving slots 115 to travel only
through fins 113.
Still referring to FIG. 1C, shell members 112 may be optionally
attached to fins 113 by any suitable means including, but not
limited to, chemical bonding, fastening with nuts, bolts, rivets,
clamps, or other mechanical means, and welding. Any number of slots
115 may be present and slots 115 may be of any suitable shape or
size. Springs or other structures may be present in slots 115,
shell members 112, or fins 113. Shell members 112 and fins 113 may
be made of the same material or may be made of different materials.
Materials may be mixed or matched as suitable for helical strake
segment 111 and its components.
Referring now to FIG. 1D, FIG. 1D is a cross sectional end view of
FIG. 1C along line B-B'. From this view, the strake segment 111
with shell members 112 and fins 113 can be more clearly seen.
Representatively, from this view it can be seen that fins 113 have
a trapezoidal cross section with curved tops. For example, fins 113
may have a base portion 170, which is held against the tubular by
the shell member 112, and a tail portion 172, which extends
radially outward to the tubular portion (and the shell portion
surrounding the tubular) and is curved at the top. The base portion
170 may be optionally curved for example to match the curvature of
the underlying tubular. Shell members 112 may include a center
portion 174, which matches the curvature of the underlying tubular
and rests on the tubular, and which is flanked by flanges or
extension members 176. The flanges or extension members 176 of
adjacent shell members 112 may form openings or gaps that the fins
113 can be positioned within or between. The flanges or extension
members 176 may extend up the sides of the adjacent fins 113 and
help to hold the fins 113 against the tubular. Shell members 112
may be optionally attached to fins 113 by any suitable means
including, but not limited to, chemical bonding, fastening with
nuts, bolts, rivets, clamps, or other mechanical means, taping, and
welding. Attachment of shell members 112 to fins 113 may be
temporary, for example for transportation or for installation, or
may be permanent through the life of helical strake segment 111.
While FIG. 1D shows three fins 113 and three shell members 112
present, any number of fins 113 and shell members 112 may be
present on helical strake segment 111.
Referring now to FIG. 1E, FIG. 1E shows a cross-sectional end view
of a strake segment similar to FIG. 1C, except in this embodiment,
helical strake segment 121 includes different cross sections for
shell members 122 and fins 123. Fins 123 extend through openings
between, or in, shell members 122, as previously discussed.
Representatively, in this embodiment, fins 123 are T-shaped in
cross section and the ends (flanges) of shell members 122 are made
to approximately match at least part of the T-shaped cross section.
Fins 123 may have other similar shapes, for example fins 123 may
have a base portion 170, such as the base of the inverted T in FIG.
1E, with a vertical member or tail 172 that is not necessarily
rectangular. Thus, fins 123 may be of any suitable cross section
with a surface to mate with an adjacent shell member 122. Note that
shell members 122 may have other openings for other fins or other
structures. Shell members 122 may have other end shapes than those
shown in FIG. 1E; in general shell members 122 will either have at
least one surface that provides interference for fins 123 being
pulled outward when an underlying tubular is present or have at
least once surface for attaching shell member 122 to an adjacent
fin 123. Openings 124 may be of any suitable shape. In FIG. 1E
openings 124 are not straight but are rather somewhat S-shaped.
Referring now to FIG. 1F, FIG. 1F shows a cross-sectional end view
similar to FIG. 1E, and includes helical strake segment 131 with
fins 133 extending through openings 134 between, or in, shell
members 132. In this embodiment, however, fasteners 135, consisting
of bolts 136 and nuts 137, are further shown attaching fins 133 to
shell members 132. Representatively, fasteners 135 may include
bolts 136 which extend entirely through the flange portions of
shell members 132 extending up the fins 133, and portions of fins
133 between the flange portions. The nuts 137 may be attached to
the end of the bolts 136 extending out of the flange portions.
Fasteners 135 can be any type of fasteners suitable for attaching,
or connecting, fins 133 to shell members 132. Representatively,
fasteners 135 can include, but are not limited to, fastening with
nuts, bolts, rivets, clamps, or other mechanical means, taping,
welding or chemical bonding. Any number of fasteners 135 may be
used for a single fin 133 or shell member 132 and fasteners 135,
bolts 136, and nuts 137 may be of any size, shape, or quantity.
Fasteners 135, bolts 136, and nuts 137 may be made of the same
material or may be made of different materials.
Referring now to FIG. 1G, FIG. 1G illustrates a perspective view of
another embodiment of a helical strake segment. Helical strake
segment 141 may include a shell 142 and fins 143. In this
embodiment, helical strake segment 141 has slit 147 running along
the length of segment 141, thus forming opposing helical strake
sides 141A and 141B, which when brought together, encircle the
underlying tubular. Slit 147 may be a substantially straight slit
(or gap) formed through shell 142 and fins 143 as shown. Shell 142
may include shell members 142A, 142B, and 142C that are attached to
each other using rivets 145. As can be seen from FIG. 1H, shell
members 142A-142C may include a center portion 174, flanked by
flanges 143, which form helically shaped extension members or fins
143, and are attached to each other using rivets 145.
Shell members 142A, 142B, and 142C each extend around part of the
circumference of helical strake segment 141. Each of shell members
142A, 142B an 142C may have edges that are raised (and extend away
from the underlying tubular) and helical in shape so that edges of
adjacent shell members 142A, 142B, and 142C can be adjoined to form
helical strake segment 141 and the edges of adjacent shell members
142A, 142B, and 142C form the fins 143 of helical strake segment
141. Any number of shell members 142A, 142B, and 142C may be
present and openings may be present in shell members 142A, 142B,
and 142C with these openings used for any suitable purpose. For
example, gaps in the edges of shell members 142A, 142B, and 142C
may be used as channels for bands in fins 143 and may even contain
springs for bands so as to accommodate changes in diameter of the
underlying tubular. While FIG. 1G shows rivets 145 used to connect
adjacent shell members 142A, 142B, and 142C, any suitable
connection method may be used including, but not limited to,
chemical bonding, fastening with nuts, bolts, rivets, clamps, or
other mechanical means, taping, and welding. Fins 143 may be of any
suitable height, shape, and thickness and do not need to be of
constant height along their length.
Still referring to FIG. 1G, shell members 142A, 142B, and 142C and
rivets 145 may be made of any suitable material including, but not
limited to, plastic, metal, fiberglass, composite, synthetic,
rubber or elastomer, and wood. Materials may be mixed or matched as
suitable for helical strake segment 141 and its components.
Referring now to FIG. 1H, FIG. 1H shows a cross-sectional end view
along line C-C' of FIG. 1G. From this view, the arrangement of
helical strake segment 141 with shell members 142A, 142B, and 142C
forming both shell 142 and fins 143 can be more clearly seen.
Helical strake sides 141A and 141B sit opposite slit 147 which
allows helical strake segment 141 to be opened and closed around an
underlying tubular such as tubular 100 in FIG. 1A.
Still referring to FIG. 1H, any number of slits 147 may be present
and thus helical strake segment 141 may consist of any number of
circumferential sections. This feature applies to all of the
helical strake segments described in this specification. While FIG.
1H shows the edges of shell members 142A, 142B, and 142C
approaching adjacent edges with a taper, thereby forming a
trapezoidal fin 143, these edges may be of any suitable geometry.
For example, edges of shell members 142A, 142B, and 142C may form
rectangular fins and helical strake segment 141 may have fins of
various geometries by modifying the edges of shell members 142A,
142B, and 142C by any suitable means.
FIG. 1I is cross section of another embodiment of a helical strake.
Representatively, FIG. 1I shows a helical strake segment 101
including a shell 102 and fins 103. The shell 102, in this
embodiment, may be made from a continuous sheet of material. The
sheet of material may be a relatively flat and relatively flexible
sheet of material that can be wrapped around the underlying tubular
(not shown). Once wrapped around the tubular, the interfacing edges
167 of the sheet of material maybe secured together at attachment
region 168. For example, the interfacing edges 167 may be welded,
taped, or otherwise secured together. In some cases, the
interfacing edges 167 may be temporarily secured together. In
particular, as will be discussed in more detail below, in some
aspects fins 103 may be stiff enough to hold the shell 102 around
the tubular, once they are positioned around the shell 102.
The fins 103 may be similar to the previously discussed fins in
that they can include a base portion 170 and tail portion 172. In
this embodiment, the base portion 170 may be positioned on the
outer surface of the shell 102. For example, the base portion 170
can be connected to the shell 102 at attachment region 169, which
could be a weld joint. The fins 103 can be attached to the shell
102 before or after securing the shell 102 around the tubular. For
example, in one aspect, the shell 102 is closed and secured at
point 168 around the tubular, and then the fins 103 can be attached
to the outer surface of the shell 102. It should further be
recognized that in some aspects, the fins 103 are stiff or rigid
enough to maintain a helical configuration on their own around a
tubular and therefore do not need to be welded to the shell, or
otherwise secured to the shell by another piece. Instead, once the
shell 102 is positioned around the tubular, the fins 103 can be
positioned around the shell 102 and will remain in place without
welding. The fins 103 may also help hold the shell 102 around the
tubular, without welding the fins 103 to the shell 102, due to
their stiff or rigid helical shape.
FIG. 1J is cross section of another embodiment of a helical strake.
Representatively, FIG. 1J shows a helical strake segment 101
including a shell 102 and fins 103. The shell 102, in this
embodiment, may be similar to the shell described in reference to
FIG. 1I in that it is made from a continuous sheet of material. The
sheet of material may be a relatively flat sheet of material that
can be wrapped around the underlying tubular (not shown). The
interfacing edges 167 of the sheet of material may be secured
together (e.g., welded) at attachment region 168 as previously
discussed. The fins 103 can be attached to the shell 102 before or
after securing the shell 102 around the tubular.
The fins 103 may be similar to the previously discussed fins,
except in this embodiment fins 103 may have a T shape.
Representatively, fin 103 may include a base portion 170 made up of
flanges 155, and a tail portion 157 that is perpendicular to the
flanges 155 of base portion 170 such that they form a T shape. The
flanges 155 (or widest portion of the fin) are attached (e.g.,
welded) to the outer surface of the shell 102 at attachment regions
169, as previously discussed. It should further be recognized that
in some aspects, the fins 103 are stiff enough to maintain a
helical configuration on their own around a tubular and therefore
do not need to be welded to the shell. Instead, once the shell 102
is positioned around the tubular, the fins 103 can be positioned
around the shell 102 and will remain in place without welding. The
fins 103 may also help hold the shell 102 around the tubular,
without welding the fins 103 to the shell 102, due to their stiff
or rigid helical shape.
In broad embodiments, the present invention is directed to a
helical strake segment including shell segments with, or without,
discrete fins. The above aspects of this invention may be mixed and
matched in any manner suitable to achieve the purposes of this
invention. Other appurtenances for connecting various components
may be utilized and each component may be manufactured by any
suitable means. One or more anti-fouling coatings or structures may
be applied to the inner surface, the outer surface, or both the
inner and outer surface of any of the helical strake segments or
components described herein. Each helical strake segment may have
any number of slits and may be divided circumferentially into any
number of section in any suitable manner including sections that
are helical in shape. Attachments may be temporary such as for
storage or installation or may be more permanent for field use. The
helical strake sections may be attached around an underlying
tubular by any suitable means including, but not limited to,
banding, bolting, clamping, and chemical bonding.
While the foregoing written description of the invention enables
one of ordinary skill to make and use what is considered presently
to be the best mode thereof, those of ordinary skill will
understand and appreciate the existence of variations,
combinations, and equivalents of the specific embodiment, method,
and examples herein. For several of the ideas presented herein, one
or more of the parts may be optional. The invention should
therefore not be limited by the above described embodiment, method,
and examples, but by all embodiments and methods within the scope
and spirit of the invention.
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